The present invention relates generally to telecommunications systems and more particularly to delay calculation for a frame relay network.
The increased need for a speed across network platforms has increased the popularity of frame relay networks. Frame relay networks provide high-speed packet switching and are generally used to connect multiple local area networks (LANs). Frame relay networks exploit the notion of virtual connections. These virtual connections provide point-to-point connections between sites. The bandwidth of each of the virtual connections may be shared among multiple applications. Delay determination is difficult in conventional frame relay networks for a couple of reasons. First, many conventional frame relay networks use connection-less infrastructures that can overcome equipment or path failures within the network. Virtual connections that are provisioned across such connection-less infrastructures may take different paths at different points in time, and, as a result, each path may have different delay characteristics.
Second, the delay may vary in accordance with resource utilization and, thus, is not constant. Frame relay networks transmit frames that may encounter queuing or buffering as they traverse the network. The degree of buffering is usually a function of resource utilization within a network. In general, as resource utilization increases, additional traffic may need to be buffered until the resources are available. This also results in a dynamic variation in delay for the virtual connections in a frame relay network.
This inability to easily determine delay in frame relay networks is frustrating to many customers. Many customers have migrated from private line environments to frame relay networks. In private line environments, the delay across connections is usually quite constant. The inability to accurately calculate delays in frame relay networks makes frame relay networks less desirable to many customers.
The present invention provides a mechanism for determining delay for virtual connections in a frame relay network. The present invention gathers information regarding the delay of one or more virtual connections and then stores this information. Clients may then receive the delay information by requesting it as needed.
In accordance with a first aspect of the present invention, a method is practiced in a frame relay network having switches. A virtual connection is provided that logically connects an originating switch in the frame relay network to a destination switch in the frame relay network. A frame is transmitted from the originating switch to the destination switch. In turn, the frame is then retransmitted from the destination switch back to the originating switch so that the originating switch receives the frame. A time value is determined to be equal to how much time expired between the transmitting of the frame from the originating switch to receiving the frame by the originating switch. This determined time value is designated as a delay measurement value for the virtual connection.
In accordance with a further aspect of the present invention, a method is practiced in a frame relay network that has storage and switches. The switches include a first and second switch that constitutes endpoints of a virtual connection. At periodic intervals, a delay measurement value is calculated for the virtual connection. The delay measurement value is stored in the storage, and access to the delay measurement value is provided to a client.
In accordance with another aspect of the present invention, a frame relay network includes a first switch, a second switch, and a connection that connects the first switch with the second switch. The frame relay network also includes a delay measurement calculator for calculating a delay measurement corresponding to how long it takes for a frame to be sent from the first switch to the second switch and back from the second switch to the first switch.